Antenna



FIG. 1 is a top, front, and right side environmenatal perspective view of an antenna, showing our new design with the broken line structure being for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a front elevational view thereof with the broken line structure being for illustrative purposes only and forming no part of the claimed design;

FIG. 3 is a rear side elevational view thereof with the broken line structure being for illustrative purposes only and forming no part of the claimed design;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a top plan view thereof. 

The ornamental design for the antenna, as shown and described. 